


forged in flames

by Seito



Category: Katekyou Hitman Reborn!, 文豪ストレイドッグス | Bungou Stray Dogs
Genre: 20YL!Tsuna, Alternate Universe - Canon Divergence, Chaos, Crack, Decay of Angels Arc (Bungou Stray Dogs), Gen, Humor
Language: English
Status: Completed
Published: 2021-01-10
Updated: 2021-01-10
Packaged: 2021-03-14 21:28:25
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,686
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28677423
Author URL: https://archiveofourown.org/users/Seito/pseuds/Seito
Summary: Honestly, the last thing Dazai expected was to be broken out of jail by the World’s Greatest Hitman: Reborn.(Or one day Tsuna found a tiger! It was not an actual tiger. But Natsu was not an actual lion so you know details.)
Relationships: Nakajima Atsushi & Sawada Tsunayoshi
Comments: 23
Kudos: 249





	forged in flames

Dazai smiled and Fydor smiled back.

Mentally though Dazai was irritated and exhausted. Being locked up in jail had been a calculated risk on his part, he needed information from Fydor about the Decay of Angels and this was the best method. It didn’t mean he liked it.

There was a loud explosion and suddenly Dazai’s cell was shaking. He looked up in time someone cutting through the top of his cell with a laser. The circle completed and into his cell, dropped a man in a black suit and fedora. “Chaos,” he greeted.

Dazai felt his jaw drop. That greeting, that hat. “You’re… Reborn?!” he sputtered. What was the World’s Greatest Hitman doing in his jail?!

“Ah, as expected from the former Demon of the Port Mafia,” Reborn said.

He knew who Dazai was?!

Reborn threw him over his shoulder. “This is a jailbreak,” he said.

What?!

-.-.-

Kunikida felt fear. The Hunting Dogs were certainly something else. He couldn’t even foresee Suehiro’s attacks. It was a sword, clearly, but it moved so fast.

He pulled out his notebook, preparing to write. “Doppo Poet: Stun-”

The ringing of metal clashing.

Kunikida looked up in shock as a man had stepped in front of him and blocked Suehiro’s attack that would have surely cut Kunikida down. His sword was coated in a blue flame.

“Maa, a swordsman in the Hunting Dogs? I hope you’ll be a good match,” the man laughed.

Who…? He looked a little like he belonged to the Port Mafia with that suit.

“Who are you?” Jouno asked, frowning.

“You don’t have time to worry about me,” the man laughed easily.

Out of nowhere, a giant purple spiked ball came crashing down on Jouno. The two Hunting Dogs jumped back to dodge it.

And then out of nowhere bullets rained down on the Hunting Dogs.

“Hey stupid Detective Agency Motherfuckers! Boss told me to pick you up for daycare!”

Kunikida turned to see Chuuya in a helicopter. The Port Mafia had really come?! They were helping?!

“Oh good timing,” the man in the suit said. “Hibari! There’s a ride here!”

Kunikida had a split second to see another man in a suit appear out of nowhere and grab Yosano and Tanizaki before making that impossible jump to the helicopter. Then he and Kenji were grabbed by the man with the sword and flying up there.

“What?” Chuuya said, as they all landed in the helicopter. “Who the hell are you two?”

They… weren’t Port Mafia? Then who?

Kunikida didn’t have time to ask these questions as the man with the sword, turned and started swinging his sword. Kunikida couldn’t see anything, but the ringing of metal suggested that he was somehow deflecting Suehiro’s attacks.

“Maa how disappointing,” the man with the sword said. He pulled out a box from within his suit, never dropping his attack. Blue flames sprung to life again, this time around a ring on his ring. “Koziro, cover our escape. _Shuuchuu Gouu._ ”

The blue flames exploded, covering the area.

“Those are Rain Flames?!” Chuuya sputtered. “You two are Vongola?!”

“Vongola?” Kunikida asked with wide eyes. The international mafia group?! The one everyone knew and feared for the chaos and insanity they inflicted? The one with people who were so strong they said to crush countries with a single person? With Dying Will Flames that functioned completely differently from abilities? Some of the most wanted criminals in the entire world were from Vongola?! They had been reaching into Japan in the last two or three years but he had no idea they were here in Yokohama.

The man with the sword laughed. “Yes! I’m Yamamoto Takeshi. You must be Nakahara Chuuya,” he said.

“You know who I am?!” Chuuya asked, bewildered.

“Of course!” Yamamoto said.

He gestured to the other man. “This is Hibari Kyouya. Don’t mind him. He’s a man of few words. I don’t suppose you could take us to Namimori?”

“And why should I do that?” Chuuya said. “My boss said to bring the Agency back to our headquarters.”

“And my boss said to bring them to Namimori,” Yamamoto said. The traces of laughter disappeared. “We’re prepared to take them and fly back to Namimori. But a helicopter will be faster.

“Unless you think you can take on two of Vongola’s Guardians by yourself, Nakahara Chuuya.”

Chuuya clenched his fist. He looked at Kunikida. “What do you want to do?” he asked.

Yamamoto pulled out his cellphone and handed it to Kunikida. “Called Atsushi.”

Hesitantly, Kunikida took it. What did he have to lose? He dialed Atsushi’s number, surprised to see it had already been saved under Atsushi’s name in Yamamoto’s cellphone.

“Yamamoto-san?” Atsushi’s voice came on the other side.

“Atsushi,” Kunikida said.

“Kunikida-san! I guess that means Yamamoto-san reached you!” Atsushi said.

“Where are you?” Kunikida asked. If Atsushi said Namimori, then they were going to Namimori.

“Namimori!” Atsushi said. “Kyouka-chan is here too. We’re fine. Are you okay?”

“Yes, we’re fine,” Kunikida said, sagging in relief. He didn’t know what was going on, but at least for now, they appeared to be safe.

“That’s great!” Atsushi said. “Then I’ll see you soon. Oh, and Kunikida-san?”

“Yes?”

“Whatever Yamamoto-san says, I deny everything.”

Atsushi hung up.

What did that mean?!

“Atsushi is in Namimori,” Kunikida said, handing back his phone and looking at Chuuya.

Chuuya clicked his tongue, irritated. He knocked on the window of the cockpit and ordered the pilot to fly to Namimori.

“Thanks!” Yamamoto said, grinning.

“Why is Atsushi in Namimori?” Yosano asked.

“Oh that’s easy,” Yamamoto said. “It’s home after all. He called us.”

Wait.

What.

When did Atsushi have a connection to Vongola?!

-.-.-

Dazai had so many questions. Reborn took him all the way back to Japan, to Namimori and didn’t explain a single thing. Dazai’s mind raced, trying to figure out why Reborn had broken him out of jail, why he was being taken to Namimori, why was Vongola even interested in this scenario?! Except he couldn’t figure it out?! What was he missing?!

Reborn pulled the car up a large house on the edge of Namimori’s town.

“We’re here,” Reborn said.

Dazai got out of the car, still unable to shake the feeling of complete bewilderment.

“Oh it looks like my guess was right.”

Dazai turned to see Ranpo coming up the street. “Ranpo-san?!”

The sound of a helicopter filled the air. Dazai saw a Port Mafia helicopter land a few feet away and out came Chuuya, Kunikida, Yosano, Kenji and Tanizaki.

“Dazai?!” Chuuya squawked at him. “Did you arrange this?!”

Oh Dazai wished he did. But he was completely lost.

“Dazai!” Yosano called out to him. “Are you alright?!”

Yes, completely fine. Just completely confused for once and Dazai couldn’t say he liked this feeling at all.

He was glad to see all of them in one piece though. They were currently being framed and hunted by the Hunting Dogs, but they were alive.

“Ah, welcome to Namimori, everyone.”

Dazai turned to see a young man approaching them in oversized hoodie and jeans. Despite his casual attire, Dazai recognized him instantly.

“You’re Sawada Tsunayoshi, Vongola Decimo,” he blurted out.

Tsunayoshi laughed. “I’ve retired from that, but yes.”

Retired?! What did that mean?!

Atsushi came rushing out of the house, Kyouka right behind him.

“Everyone! Dazai-san!” He tackled Dazai in a hug.

Dazai gave up and embraced Atsushi’s hug. He had no idea what was going on.

Reborn pulled Atsushi off of Dazai. “Alright, we got your friends here, brat. It’s now time for your lessons.”

Atsushi paled. “N-now? But they just got here.”

Reborn dragged him off. “You’ve been gone for a year. You better have improved to my standards, brat.”

“Hiieee, Tsuna-nii!” Atsushi called out, reaching out.

“Have fun, Atsushi,” Tsunayoshi said, waving.

...Atsushi knew Vongola?

“How do you know Atsushi-kun?” Dazai asked.

“Oh that’s simple,” Tsunayoshi said. “He’s one of my wards.”

What?!

Tsunayoshi smiled. “Why don’t we go inside and we can talk?”

Dazai had so many questions.

-.-.-

-Two Years Earlier-

Tsuna looked at the scene before him, bemused.

There was a white tiger in his lawn, munching at his vegetables. The vegetable garden he worked very hard to grow. He was a little upset about this to be honest.

Confidently, calmly, he strolled over the white tiger and immediately punched it with a well placed, Sky Flame coated punch.

And it turned back into a young boy.

“Well,” Tsuna said. “The tiger wasn’t a tiger. Then again, Natsu isn’t really a lion, so still not the weirdest thing in my life.” He picked up the young boy and carried him into the house.

-.-.-

“And Atsushi has been here since,” Tsuna said, sipping his tea. “Or he was until training went awry one day and the next thing I know I’m getting a call from him saying he’s in Yokohama, has a job at the Armed Detective Agency and would like to really stay and see what it’s like.”

It was a little sad that Atsushi had left so soon, but Tsuna was more than happy with the idea that Atsushi seemed to have found what he wanted to do with his life.

“Atsushi is a part of Vongola,” Kunikida said, rubbing his eyes. “I feel like my life is a lie.”

“Oh, no. I mean technically Vongola doesn’t exist anymore,” Tsuna said.

Everyone stared at him.

“Well, it sorta exists,” Tsuna said. “It’s more of a vigilante group than a mafia group these days, but that image seems to persist. I promised my ancestor that I would clean up Vongola and return it to its roots.”

And Tsuna did. It took him nearly twenty years to do so, but he did it. Oh everyone grumbled and dragged their feet, and technically Tsuna was ignoring the still very active assassination branch that Varia and Reborn were still maintaining. But by the time Tsuna turned 35 he looked at what he had done, nodded to himself and retired.

Except his Guardians (and Reborn) decided to return with him to Namimori.

And suddenly the rumors that Vongola was expanding to Japan were kicking up again.

But Tsuna _was_ retired. For a full three years now!

It wasn’t his fault that no one believed him and that Xanxus kept sending him paperwork for him to do as Decimo.

“Technically, Vongola doesn’t exist and technically this means Atsushi isn’t a part of Vongola,” Tsuna said with a smile.

The look on everyone’s faces said they didn’t believe him.

Too bad.

Explosions went off in the background.

Chuuya glanced at the window. “What’s going on out there?”

“Training,” Tsuna said. “Reborn has standards.”

Everyone from the Agency nervously glanced at the window.

Well, it was Reborn after all. Tsuna didn’t blame them. But Atsushi would be fine. If Tsuna survived Reborn’s training, Atsushi could too.

Dazai meanwhile sighed. “This is why Atsushi-kun doesn’t even bat an eyelash at Akutagawa-kun. He has Reborn as a mentor.”

Mmm yes. Tsuna still had to meet Akutagawa one day. He didn’t appreciate the fact that Akutagawa had cut off Atsushi’s leg. Thankfully Atsushi had grown it back, but that could have ended so poorly.

Atsushi had tried to skim over the fact that Akutagawa had cut off his leg, but Tsuna knew. He always knew.

That was Hyper Intuition for you.

The door opened and Atsushi trugged in, covered head to toe with dirt and a few scrapes that Tsuna could already see healing thanks to his ability.

“Tsuna-nii,” Atsushi asked, groaning, “when did you stop getting tutoring from Reborn?”

“I was 34,” Tsuna said calmly. Reborn didn’t consider any of his students graduated until they beat him in a fight. Dino finally accomplished this when Tsuna had turned 30.

“How long is it going to take me?!” Atsushi said, horrified.

“And once you graduate from training, it just becomes sparring,” Tsuna said. To which Reborn still threw Tsuna out of his bed nearly every other morning.

Atsushi groaned and headed off to the bathroom.

Tsuna beamed, looking back at Atsushi’s friends (and enemy?). “He’s such a good kid,” Tsuna said. “I’m really happy you all have been looking after him so well.”

They all stared at him.

Dazai just sighed again. “The reason why Atsushi was able to defuse the bomb for his entrance exam was because of Reborn.”

“Actually he learned how to defuse bombs from Gokudera, my Storm Guardian,” Tsuna said proudly.

“Skydiving?” Dazai weakly asked.

“Mukuro, my Mist Guardian,” Tsuna said. “Also he is also the reason why Atsushi can sneak anywhere without being noticed.”

Dazai covered his face with his hands. “I’m so ashamed of myself for not figuring this out sooner.”

Tsuna laughed.

“How long have you known, Ranpo-san?” Dazai asked, resigned.

“About four days and I’m just as annoyed as you are,” Ranpo said. “I knew he was similar to you but I only figured out Vongola recently.”

Atsushi came out of the bathroom, freshly clean and took the empty seat next to Tsuna. All of his friends snapped to their feet.

“Atsushi! When were you going to mention you knew Vongola?!” they chorused.

Atsushi blinked, glancing at Tsuna. “Vongola is mostly dismantled and I thought it wasn’t that big of a deal?”

“He doesn’t know,” Ranpo said flatly.

“He doesn’t know,” Dazai said with a sigh.

“He gets Vongola involved and he doesn’t know,” Kunikida said.

Chuuya frowned, looking at Atsushi. “You’re such a strange kid. How do you not know?”

Atsushi blinked at their reactions. He looked at Tsuna. “Did you leave something out of your explanation, Tsuna-nii?” he asked, eyes narrowing in suspicion.

“Of course not,” Tsuna said. He explained Vongola in a relatively… sane way. There was no need to explain what Vongola Style meant to Atsushi. It was an outdated explanation, except in terms of parties. And Atsushi knew about Vongola Style Parties.

Frankly, Tsuna was proud that Atsushi decided to take after him and just look at the chaos, sigh and carry on.

Tsuna felt his phone vibrate. He pulled it out to see a message from Yuni.

_Yuni: the leader of the Hunting Dogs is also the leader of Decay of Angels. He will have the Page that will reverse this._

Ah. Excellent. Then it was to their advantage the Hunting Dogs were coming after them. Tsuna forwarded the message to Gokudera.

He felt a ping from Hyper Intuition and sent another message to Gokudera.

“Atsushi, you may want to grab your earplugs,” Tsuna said. Atsushi’s ears were very sensitive thanks to his ability. He could hear so many things.

Atsushi went scrambling for his earplugs and put them on just in time for an explosion of rainbow colored flames to go off in the distance.

Tsuna sipped his coffee.

“W-what was that?” Yosano asked, eyes wide, staring out the window.

“What the fuck,” Chuuya said, just as stunned.

The fires died down and Atsushi pulled off his earplugs. He huffed. “Everyone is going wild again,” he said with a resigned but ultimately bored tone.

Everyone stared at him.

“That was really pretty,” Kenji said.

The door opened and Reborn strolled in.

“Your Guardians chewed out the Hunting Dogs,” Reborn announced. He smirked. “And I sniped Fukuchi.”

Reborn reached into his inside his jacket and pulled out a piece of paper and handed it to Tsuna.

Tsuna took it, glancing over it. Perfect. Just like Yuni foresaw. He then handed it to Atsushi. “Here you go Atsushi. This is The Page you wanted.”

Atsushi looked at him with wide eyes before pouncing Tsuna for a hug. “Thank you, thank you, Tsuna-nii.”

Tsuna patted him on the head. “Of course, Atsushi.”

Now that solved the whole ‘Armed Detective Agency being framed’ issue, it was time to clean up a few other issues that Tsuna had been sitting on.

He smiled at Atsushi’s friends who were all staring at him and Atsushi and tilted his head. “Now which one of you can arrange so I can talk to Akutagawa-kun?”

“Tsuna-nii!”

“Atsushi, he cut off your leg. I’m going to have _words_ with him.”

**Author's Note:**

> *snicker* Throwing KHR’s insanity at the BSD cast who usually have high tolerances but sometimes enough is enough. Haha
> 
> Please leave a review on your way out.


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